Heretofore, such a chip type component has been structured as shown in FIG. 1. FIG. 1 shows a cross-sectional view of a square plate type chip resistor, in which designated at reference numeral 1 is a glass coating film, 2 an alumina insulating substrate, 3 a resistor substance, 4 a silver electrode film, 5 a nickel film, and 6 a solder or tin film precipitated with the electroplating method. Other relevant techniques are also described in Japanese patent Laid-Open NO. 54-26458 (1979), Utility Model Publications Nos. 56-21282(1981) and 56-21283(1981), Pat. Publication No. 58-10843 (1983), and Utility Model Laid-Open No. 60-192401(1985), etc.
In such conventional structure, the solder or tin film 6 of FIG. 1 is of a plated film having a coarse surface condition as shown in FIG. 2 and, therefore, it has a very large surface area. For this reason, this type film is liable to occlude or adsorb foreign matters thereon. There has thus been a problem of some possibility that the electrode surface may be subjected to chemical changes such as oxidation for a long period of storage, and a soldering failure may be caused in solder-mounting of the chip onto a printed board.
The present invention is intended to solve this problem and has for its object to reduce the surface area of the electrode portion of a chip type component and smooth the surface thereby improving the wetness of solder and enhancing the reliability of soldering after a long period of storage.